1. Field of the Invention
The invention relates to the production of methane from carbon monoxide. More particularly, it relates to a methanation process capable of effectively utilizing the CO content of waste effluents as feed gas streams.
2. Description of the Prior Art
The production of low-cost methane as a replacement for natural gas has been the subject of considerable interest in light of the energy requirements of industrial societies throughout the world. The COthane process has been developed in response to such interest and concerns. It is particularly advantageous in that this process is capable of utilizing dilute carbon monoxide-containing gas streams without the necessity for the preliminary concentration that has precluded the use of such streams in conventional techniques for the production of methane from carbon monoxide and hydrogen. Thus, waste streams such as the effluent from blast furnace operations, carbon black off-gas, undergound coal gasification and the like can be effectively utilized for the production of methane although previously unsuitable as useful sources of CO.
The COthane process is a cyclic, essentially two-step process in which a surface layer of active surface carbon is deposited on a catalyst and is then contacted with steam or hydrogen to convert the active surface carbon to methane and carbon dioxide. This essentially two-step process is repeated in cyclic operations without the need for regenerating the catalyst as a necessary additional step of the cyclic operation. Upon separation from carbon dioxide by conventional means, the methane is recovered in the form of low-cost relatively pure product, with the process effectively utilizing the carbon values of dilute carbon monoxide-containing waste gas streams or other such sources of feed gas for the process.
There is, of course, a desire in the art to continually improve the available methanation technology. With respect to the COthane process in particular, it is desirable to develop processing improvements and modifications to enhance the overall process, especially with respect to the utilization of the CO content of the waste gas streams that are of particular value as feed gas streams for the process. It is also highly desirable to assure that the secondary or supporting steps associated with the essentially two-step cyclic process as described above are minimized to further enhance the economic attractiveness of the process and thereby to decrease the cost of the methane product obtained therefrom.
It is an object of the invention, therefore, to provide an enhanced process for the low-cost production of methane from carbon monoxide-containing gas streams.
It is another object of the invention to provide improved utilization of the CO content of feed gas streams used in the cyclic, essentially two-step production of methane.
It is a further object of the invention to enlarge the scope of waste streams suitable for use as an effective source of CO in said cyclic, essentially two-step process.
It is a further object of the invention to reduce the supporting steps to be employed in association with said essentially two-step process, thereby reducing the overall cost of the methane produced thereby.